Pneumatic lift struts (gas springs) are widely used to either partly or totally counterbalance engine compartment hoods, trunk lids, rear windows and tailgates of vehicles to facilitate opening them and to hold them open. The force outputs of gas springs may vary considerably with changes in ambient temperature. That is, at low ambient temperatures a gas spring produces a force that can be significantly lower than the force produced at higher ambient temperatures. To offset this effect a temperature compensating valve (TCV) assembly is assembled into pneumatic lift strut bodies. The TCV assembly separates the gas chamber of the gas spring into two separate pressure chambers. When the valve is closed (for example at temperatures above 4 degrees C.) the gas spring functions using a main pressure chamber acting on a piston and rod assembly. At lower ambient temperatures (for example at temperatures below 4 degrees C.) the valve opens, allowing the gas spring to operate and provide an output, or lift force on the piston and rod assembly, based on the volume of gas in the main pressure chamber and an additional volume. The additional volume is contained in a secondary pressure chamber.
In some cases, such as following damage to the vehicle following a crash, gas in the main pressure chamber may escape from the pneumatic lift strut due to leakage at a lift rod seal. In cases in which the pneumatic lift strut temperatures are elevated the gas pressure in the secondary pressure chamber may overcome the retention forces holding the TCV assembly in place in the pneumatic lift strut body causing it to dislodge from its seated position. The movement of the TCV assembly may be rapidly arrested at an end of the pneumatic lift strut body resulting in damage to the piston and rod assembly, such as separation of the components from one another.